Washington Mudslide Creates Environmental Hazards

A landslide last month northeast of Seattle destroyed dozens of homes and killed at least 33 people. Now the small rural community of Oso on the edge of the Cascade Mountains is moving from search and rescue into clean-up mode. Officials are just beginning to assess the environmental and public health risks in the area.

Ashley Ahearn, from member station KUOW in Seattle, visited the site and has more.

(SOUNDBITE OF MACHINERY)

ASHLEY AHEARN, BYLINE: You can see the plywood boards for people can get out to the site, an American flag off in the distance, people working really hard - a lot of hard hats - and a lot of gray, mucky water flowing out of that site right now.

MAJOR WILLIAM POLA: Personnel, even canines - don't use dogs as they come off the site - they're going to get decontaminated either here. There's also a decon tent to your rear. We'll stop at that on the way back out.

AHEARN: Major William Pola is with the Army National Guard. Behind where he's standing, workers pressure wash massive trucks with hot water and mild detergent as they leave the landslide zone. Other responders somberly wash off their boots nearby. It's a standard precautionary measure, says Dick Walker. He's a spills expert with the Washington State Department of Ecology.

DICK WALKER: This really is just mud. There's really nothing terribly bad in here for a situation. We're finding the chemical hazards are very, very small.

AHEARN: But there is a lot of mud here - 10 million cubic yards. That's enough to fill three large baseball stadiums. The mud engulfed 42 homes. Propane tanks floated to the surface of the liquid debris field. Those are easy to remove. Septic tanks, cars and household chemicals remain buried.

WALKER: But really, that's very minimal with the volume of soil that has been dumped on that and spread around. And some of this is extremely deep and some of that material we may never recover.

AHEARN: Along a trail by the Stillaguamish River a child's soccer ball sits in the rain. When the slide hit, families were going about their usual Saturday mornings - kids playing in the woods, parents mowing lawns. Most of the dead have now been removed, though there are still people missing.

Dr. Richard Bradley is a physician with the Federal Emergency Management Agency.

DR. RICHARD BRADLEY: Yes, we have a potential exposure for blood and body fluids. But when you look at whatever we had was diluted in over a million cubic yards of dirt, the risk to the individual rescuer going in is really quite small.

AHEARN: Bradley says rescue workers are more likely to injure themselves clambering around the debris field than they are at risk for exposure to biohazards.

The mud tumbled 600 feet down the mountainside and blocked the Stillaguamish. Then it continued south, and Dick Walker, with the State Department of Ecology, says it buried the neighborhood on the other side of the river.

WALKER: Because the mudslide pushed everything inland, it pushed everything away from the river. So most of the household hazardous waste items that we're finding are really back away from the waters edge. The vehicles we're finding are back away from the water's edge. And because of the slope of the land, we don't believe that anything's going to get into the river from the chemical perspective.

AHEARN: Walker says his department has taken some water samples downstream from the slide zone and has not found evidence of chemical contamination. More sampling will be done in the coming months.

Springtime in the Northwest means blue-green rivers frothing with snowmelt but this river looks different. The Stillaguamish is a morose gray, littered with broken trees. Fish experts say all that muck and debris will harm the threatened salmon and steelhead that spawn in this stretch of river. But it's too soon to know how much those populations will suffer.

For now, the focus remains on the overwhelming loss of human life along this ravaged stretch of the Stillaguamish.